2304
Inorg. Chem. 1980, 19, 2304-2307 Contribution from Corporate Research-Science Laboratories, Exxon Research and Engineering Company, Linden, New Jersey 07036
Syntheses and Reactions of (Halomethylidyne)trihydridotriruthenium and -osmium Nonacarbonyl Clusters JEROME B. KEISTER* and TINA L. HORLING Received November 21, 1979 Halomethylidyne clusters H3M3(p3-CX)(CO), (M = Ru, X = C1, Br; M = Os, X = Br) are prepared by treatment of H3M3(p3-COCH3)(C0),with the corresponding boron trihalide. The ruthenium cluster H3R~3(p3-CBr)(C0)9 reacts with AlC13 and then methanol to give H3Ru3(p3-CC02CH3)(C0),and with A m 3 in C6H5R(R = H, CH3) to give H3Ru3(p,-CC,H,R)(CO),. Under basic conditions the cluster forms H3R~3(p3-COC2H5)(CO)9 with ethanol and HRu,(p-CN(C2Hs)2)(CO),owith diethylamine. With tri-n-butyltin hydride, H3Ru3(p3-CH)(CO), is prepared from the bromide derivative.
Introduction Since their discovery over 20 years ago, methylidynetricobalt complexes of the general formula Co3(p3-CY)(C0), (Y = halogen, alkyl, aryl, carboxyl, etc.) have become perhaps the most extensively studied metal clusters. As a result, much is known about the structures, physical and chemical properties, and bonding of these unusual molecules.' While the Co3(p3-CY)(CO), clusters exhibit exceptional thermal and air stability, only a handful of related clusters of metals other than cobalt are known. Until recently, examples from the iron triad were limited to H 3 R ~ 3 ( p 3 - C C H 3 ) ( C 0 ) 9 ,H30S3(p32 CCH3)(C0),,3 and H30s3(p3-CH)(C0)9.4Thus, until now it has not been possible to extend the wealth of knowledge about the properties of methylidynetricobalt clusters to other M3CY systems. Recently one of us reported convenient and high-yield syntheses of the methylidyne clusters H3Ru3(p3-COCH3)(CO), and H30s3(p3-COCH3)(C0)9.5 These molecules are isostructural (see Figure 1) with the Co,(p,-CY)(CO), series and represent the first functionalized alkylidyne clusters of the iron triad. Because of their ease of preparation, we felt that these clusters might provide convenient entries into the series of clusters H3M3(p3-CY)(C0)9(M = Ru or Os) analogous to that of the cobalt system. Furthermore, these molecules would offer additional possibilities for chemical reactivity and structural studies by virtue of the three hydride ligands. For these reasons we have explored the chemistry of the H3M3(p3-CY)(C0),system. We now report the syntheses of H3R~3(p3-CY)(C0)9, Y = C1, Br, C0,CH3, C6H5,C6H5CH3, OC2H5, and H, and of H30s3(p3-CBr)(C0),and compare these clusters with their cobalt analogues. Experimental Section Methods of Characterization. Infrared spectra (Table I) were recorded on cyclohexane solutions with a Beckman 4250 spectrophotometer and were calibrated by using the 21 38.5-cm-' absorption for cyclohexane or using polystyrene. Proton NMR spectra were obtained on Varian CFT-80 or EM-360 instruments. Mass spectra were recorded by Mr. Carter Cook of the University of Illinois Mass Spectroscopy Laboratory, using a Varian CH-5 instrument at 70 eV and a solids probe temperature of 25-150 "C. Elemental analyses were performed by Galbraith Laboratories. Chemicals. The clusters H3Ru3(p3-COCH3)(CO),and H30s3(y3-COCH3)(C0), were synthesized as previously d e ~ c r i b e d .Boron ~~ tribromide and boron trichloride were obtained from Aldrich and aluminum trichloride was obtained from MCB, and all were used without further purification. Tributyltin hydride was purchased from Alfa. H3Ru3(fi3-CBr)(C0),. To a stirred solution of H3Ru3(p3COCH3)(C0)9(125 mg, 0.208 mmol) in dichloromethane (100 mL) was added boron tribromide (50 pL, 0.538 mmol) under nitrogen. *To whom correspondence should be addressed at the Department of Chemistry, State University of New York at Buffalo, Buffalo, N.Y. 14214.
Table I. Infrared Spectra I R (in cyclohexane), 2150-1600 cm-'
cornud
2106 w, 2076 s, 2036 s, 2029 m, sh, 2014 m, 2000 w 2107 w, 2077 s, 2014 s, 2022 vs, 2013 m, 2008 m, 1995 w 2086 s, 2080 w, 2040 s, 2030 m, 2000 vw, 1992 vw 2087 s, 2069 vw, 2032 vs, 2021 m, 1990 w 2087 s, 2080 w, 2042 s, 2029 m, 1990 w 21 14 vw, 2090 s, 2081 m, 2040 s, 2030 m, 2021 w, 1685 w 2106 vw, 2080 s, 2035 s, 2031 m, sh, 2020 m, 2017 m, sh, 1993 vw 2108 vw, 2075 s, 2036 s, 2020 m 2107 w, 2077 vs, 2036 vs, 2029 m, 2014 m, 2000 w 2096 w, 2056 s, 2046 s, 2022 s, 2008 s, 1999 m, 1996 s, 1985 w 2081 s, 2034 s, 2019 m, 1985 w After 30 min the solution was evaporated to dryness, and methanol (1 0 mL) was added to destroy any residual boron tribromide. Then the product mixture was purified by preparative thin-layer chromatography on silica gel eluting with dichloromethane-hexane (1:5 by volume). A single bright yellow band yielded H3Ru3(~,-CBr)(CO), (1 16 mg, 86%) after extraction. 'H N M R (CDC13): T 27.80 (s). m / e 660 (104R~381Br). Anal. Calcd for RU,C,~H,O,B~:C, 18.46; H, 0.46; Br, 12.31. Found: C, 18.56; H, 0.43; Br, 11.97. H30~3(~3-CBr)(C0)9. To a solution of H30s3(p3-COCH3)(CO), (86 mg, 0.10 mmol) in dichloromethane (20 mL) was added boron tribromide (40 pL, 0.4 mmol) under nitrogen with stirring. After 5 min the solution was evaporated to dryness with vacuum and methanol (5 mL) was added. Then the solution was evaporated to dryness and the residue was purified by thin-layer chromatography on silica gel eluting with dichloromethane-hexane (1:5). The only observed product was H30s3(p3-CBr)(C0),(89 mg, 98%). 'H NMR (CDCI3): T 29.2 (s). m / e 924 (1920s:1Br). Anal. Calcd for Os3Cl0H3OgBr:C, 13.08; H, 0.33. Found: C, 13.24; H, 0.30. (1) (a) Seyferth, D. Adu. Organornet. Chem. 1976, 14, 97. (b) Penfold, B. R.; Robinson, B. H. Acc. Chem. Res. 1973, 6, 73. (2) (a) Canty, A. J.; Johnson, B. F. G.; Lewis, J.; Norton, J. R. J . Chem. SOC.,Chem. Commun. 1972, 1331. (b) Sheldrick, G. M.; Yesinowski, J. P. J . Chem. SOC.,Dalton Trans. 1975, 873. (3) (a) Deeming, A. J.; Underhill, M. J . Chem. SOC.,Chem. Commun. 1973, 277. (b) Yesinowski, J. P.; Bailey, D. J. Organornet. Chem. 1974, 65, C21. (4) (a) Azam, K. A,; Deeming, A. J. J. Chem. SOC.,Chem. Commun. 1977, 472. (b) Calvert, R. B.; Shapley, J. R. J . Am. Chem. SOC.1977, 99, 5225. (5) (a) Keister, J. B. J . Chem. SOC.,Chem. Commun. 1979, 214. (b) Johnson, B. F. G.; Lewis, J.; Orpen, A. G.; Raithby, P. R.; Suss, G. J . Orgunomet. Chem. 1979,173, 187. (c) Gavens, P. D.; Mays, M. J. Ibid. 1978, 162, 389.
0020-1669/80/ 13 19-2304$01 .OO/O 0 1980 American Chemical Society
Inorganic Chemistry, Vol. 19, No. 8, 1980 2305
I
r-
L
I
Figure 1. Structure of H3M3(p3-CY)(C0)9(M = Ru, Y = OCH,, O C ~ H SCI, , Br, COzCH3, C&5, CsH4CH3, H; M Br)
.
OS,Y
OCH,,
eluting with dichloromethane-hexanes (1: 10 v/v). The first band eluted was unreacted H,RU,(~,-CB~)(CO)~ (20 mg, 10%). The second band was H3Ru3(p3-COC2H5)(CO)9 (134 mg, 72%). IH NMR (CDCl,): 7 27.20 (s, 3 H), 8.30 (t, 3 H), 5.92 (4, 2 H), J = 6.9 Hz. m / e 644 ('"''Ru~). Anal. Calcd for Ru3Cl2H8OI0:C, 23.41; H, 1.30; Ru, 49.27. Found: C, 23.33; H, 1.23; Ru, 49.52. HRU~(~-CN(C~H,),)(CO)~~ To a solution of H , R U ~ ( ~ , - C B ~ ) ( C O ) ~ (220 mg, 0.34 mmol) in hexane (50 mL) under 1 atm of carbon monoxide was added diethylamine (0.35 mL, 3.4 mmol). The solution was heated for 3.5 h at 55 OC with stirring. Then the solution was evaporated to dryness and the residue was purified by chromatography on silica gel eluting with dichloromethane-hexanes (1:lO v/v). The first band eluted was unreacted H3Ru3(p3-CBr)(C0)9(61 mg, 28%). The second band was H R U ~ ( ~ - C N ( C ~ H ~ ) ~(65 ) ( mg, C O 28%). ) ~ ~ The product is also formed in the absence of carbon monoxide. IH NMR (CDC13): 7 24.60 (s, 1 H), 8.38 (t, 6 H), 5.70 (q, 4 H), J = 7.4 Hz. m / e 677 (Io4Ru3). Anal. Calcd for R u ~ C I S H ~ ~ O ~ O N : C, 26.95; H, 1.65; N, 2.10. Found: C, 26.26; H, 1.89; N, 2.09. H,RU~(~,-CH)(CO)~. To a solution of H , R U ~ ( ~ ~ - C B ~ ) (1 ( C21O ) ~ mg, 0.187 mmol) in dry hexanes (25 mL) under nitrogen was added tributyltin hydride (0.15 mL, 0.56 mmol). The solution was stirred at 50 OC with carbon monoxide bubbling through for 3.5 h. Then the solution was evaporated to dryness with vacuum, and the residue was purified by thin-layer chromatography on silica gel eluting with hexane. The second yellow band was H , R U ~ ( ~ , - C H ) ( C O(18 ) ~ mg, 17%). IH NMR (CDCI,): 7 27.82 (s, 3 H), 0.25 (s, 1 H). m / e 580 (I"Ru3). Anal. Calcd for Ru3CIOH409:C, 21.01; H, 0.71. Found: C, 21.14; H, 0.79.
H3R~3(p3-CC1)(C0)9. To a solution of H3R~3(p3-COCH3)(C0)9 (147 mg, 0.244 mmol) in dichloromethane (70 mL) was added boron trichloride (1 .O mL, 1.O mmol) under nitrogen. After 2 h the solution was evaporated to dryness with vacuum and the residue was purified by preparative thin-layer chromatography on silica gel eluting with dichloromethane-hexanes (1: 10). The product H,Ru,(~,-CC~)(CO)~ was isolated after extraction (66 mg, 45%). 'H N M R (CD2C12): 7 27.87 (s). m / e 616 (104Ru337C1).Anal. Calcd for Ru3CloH309CI:C, 19.82; H, 0.50; C1, 5.86; Ru, 50.04. Found: C, 19.70; H, 0.38; Cl, 5.60; Ru, 49.80. H3Ru3(p3-CC02CH3)(C0)9. To a solution of H,RU,(~,-CB~)(CO)~ (90 mg, 0.138 mmol) in dry dichloromethane (50 mL) was added aluminum trichloride (122 mg, 0.91 mmol) with carbon monoxide bubbling through the solution. After 10 min TLC showed no starting Results material remaining and methanol (1 mL) was added. The resulting Syntheses and Characterizations of H3M3(p3-CX)(C0)9 (M solution was treated with 10% hydrochloric acid, and the organic layer = Ru, X = C1, Br; M = Os, X = Br). One of the most was dried over magnesium sulfate, filtered, and evaporated to dryness. extensively studied members of the alkylidynetricobalt series The residue was purified by preparative thin-layer chromatography is CO,(~,-CCI)(CO)~, and its chemistry is well developed. To on silica gel eluting with dichloromethane-hexanes (15). The second get the best comparison of the chemistry of the H3M3(p3yellow band was extracted with dichloromethane-methanol to give H , R U ~ ( ~ ~ - C C O ~ C H , ) ((33 C Omg, ) ~ 38%). CY)(CO), systems with that of the cobalt analogue, it was IH N M R (CDC13): 7 27.82 (s, 3 H), 5.96 (s, 3 H). m / e 638 desirable to prepare halogen derivatives from H3M3(p3(IWRu3).Anal. Calcd for R u ~ C ~ C, ~ 22.88; H ~ H, ~ 0.96; ~ ~ Ru, : 48.18. COCH3)(C0)9. This was readily accomplished in high yield Found: C, 23.01; H, 1.00; Ru, 47.99. by treating the methoxy compounds with an excess of the H3Ru3(p3-CC,J35)(CO)g. In a 50-mL, three-necked flask equipped appropriate boron trihalide in dichloromethane: with nitrogen inlet, stirring bar, and dropping funnel was placed 25 "C benzene (5 mL) and aluminum trichloride (200 mg, 1.5 mmol). Then H,Ru,(~~-COCH,)(CO)~ BX, (X = C1, Br) a solution of H3Ru3(p3-CBr)(CO)g(84 mg, 0.13 mmol) in benzene H,Ru,(r,-CX)(CO), (10 mL) and dichloromethane (10 mL) was added dropwise. The 25 "C solution turned red after addition. After 15 min the red solution was H,OS~(~,-COCH,)(CO)~BBr, poured into 50 mL of dilute hydrochloric acid (10%) and the organic H,OS,(r3-CBr)(C0)9 layer separated. The aqueous portion was washed twice with IO-mL portions of dichloromethane. Then the organic portions were comThe halide products are easily purified by thin-layer chrobined, dried over magnesium sulfate, filtered, and evaporated to matography after destruction of unreacted boron trihalide. dryness. The residue was purified by preparative thin-layer chroThe ruthenium clusters are bright yellow crystalline solids, matography on silica gel eluting with cyclohexane to give one yellow while H,OS,(~,-CB~)(CO)~ is pale yellow. All are air-stable; band, which was extracted with dichloromethane to give upon in particular, H,RU,(~,-CB~)(CO)~ is considerably more stable evaporation yellow crystalline H3R~3(p3-CC6H5)(C0)9 (80 mg, 95%). to oxidation than the methoxy precursor and is a convenient 'H NMR (CDCI,): 7 2.3-2.9 (m, 5 H), 27.49 (s, 3 H). m/e 656 (IWRu3). Anal. Calcd for R u ~ C ~ C, ~ 29.66; H ~ ~H, ~1.25. : Found: starting material for functionalization of the methylidyne C, 29.68; H, 1.33. carbon. HJtu3(p3-CC&I&H,)(CO)~ To a mixture of aluminum trichloride The compounds H,RU,(F~-CX)(CO)~ (X = C1, Br) and (325 mg, 2.43 mmol) in toluene (25 mL) in a three-necked, 100-mL H30~3(p3-CBr)(C0)9 have been fully characterized by inflask equipped with nitrogen inlet and stirring bar was added a solution frared, 'H NMR, and mass spectroscopy, as well as by eleof H3Ru3(p3-CBr)(C0)9(200 mg, 0.31 mmol) in toluene (25 mL) mental analysis. The infrared spectra (Table I) in the terminal from a dropping funnel. After 15 min the red mixture was filtered carbonyl region are very similar to those of the methoxy and the filtrate was evaporated to dryness and purified by preparative precursors, but the absorptions are shifted to slightly higher thin-layer chromatography on silica gel eluting with dichloroconsistent with the electron-withdrawing nature methane-hexanes (1:s v/v) to yield H , R U ~ ( ~ ~ - C C ~ H ~ C H(54 ~ ) ( C O )frequencies, ~ mg, 26%). The red solid in the filter was treated with methanol and of the halide substituent. Each compound displays a single similarly purified to give additional product (75 mg, 37%). high-field resonance in the 'H NMR spectrum attributable IH NMR (a~et0ne-d~): 7 27.35 (s, 3 H), 7.70 (s, 1.7 H), 7.67 (s, to three equivalent bridging hydride ligands. The mass 1.3 H), 2.3-3.1 (m, 4 H). m / e 670 (IMRu3). Anal. Calcd for spectrum for each displays the molecular ion and ions derived R u ~ C ~ C, ~ 30.85; H ~ ~H, ~1.52. ~ : Found: C, 31.03; H, 1.57. from successive loss of carbonyl ligands down to the bare H3Ru3(p3-COC2H5)(CO)g. To a solution of H , R U , ( ~ ~ - C B ~ ) ( C O ) ~ M3CX+ fragment and finally the M3C+ ion. Although the (196 mg, 0.302 mmol) in distilled ethanol (45 mL) under nitrogen three hydride ligands are observed in the highest mass envewas added sodium ethoxide (56 mg, 0.83 mmol). After the mixture lope, they are gradually lost during fragmentation and because was stirred for 5 min at 35 OC, ammonium chloride was added and of the number of isotopes for each composition the average the solution was evaporated to dryness with vacuum. Then the residue number of hydrogens in each ion is difficult to determine. was purified by preparative thin-layer chromatography on silica gel
+
+
-
-
2306 Inorganic Chemistry, Vol. 19, No. 8, 1980 Doubly charged ions H,M3CX(C0),-,2+, n = 0-9, are quite intense for H30s3(p3-CBr)(C0),but very weak for the ruthenium clusters. With the halide derivatives in hand the reaction chemistry of these molecules was compared with that of C03(p,CCl)(CO),. Our work has focused upon three types of reactions: substitution of the halogen, promoted by aluminum trihalides, nucleophilic displacements, and free radical substitution. Our work has concerned almost exclusively reactions of the ruthenium derivatives, but the osmium clusters are expected to behave similarly.6 Halide Substitutions Promoted by Aluminum Trichloride. Treatment of C O ~ ( ~ ~ - C C I ) ( C with O ) aluminum ~ trichloride in inert solvents results in the formation of a moderately stable "acylium" cation C O ~ ( C C O ) ( C O ) ~This + . species has been isolated as the hexafluorophosphate salt, but its structure is still unknown. Upon the addition of nucleophiles, such as alcohols or primary or secondary amines, the cation rapidly reacts to give carboxylic acid derivatives Co3(p3-CY)(CO),, Y = C 0 2 R , C(0)NR2, e t ~ . l ~ , ~ The reaction of H3Ru3(p3-CBr)(C0)9with aluminum trichloride is similar to that observed for the cobalt analogue. Treatment of a dichloromethane solution of the ruthenium cluster under either a nitrogen or carbon monoxide atmosphere with excess aluminum trichloride causes gradual darkening of the yellow solution, presumably due to the formation of the H,RU,(CCO)(CO)~cation. Upon the addition of methanol the color of the solution immediately darkens to orange, and after chromatography H3R~3(p3-CC02CH3)(CO)9 is isolated in 38% yield. Characterization of H,Ru,(~,-CCO~CH,)(CO)~ by infrared, 'H NMR, and mass spectroscopy is consistent with the proposed structure (Figure 1). The infrared spectrum (Table I) between 2150 and 1900 cm-' is very similar to those of the other methylidynetriruthenium clusters; the C=O stretch of the ester moiety appears at 1685 cm-I.* The 'H N M R spectrum displays two singlets of equal intensity at T 5.96 and 27.82, assigned to the methyl group and hydrides, respectively. The molecular ion and the usual fragmentation pattern are observed in the mass spectrum. Another reaction of H , R U ~ ( ~ , - C B T ) ( C O promoted )~ by aluminum trichloride in the presence of arenes gives arylmethylidyne clusters. Treatment of a benzene solution of the bromide derivative with excess aluminum trichloride produces H3R~3(p3-CC6HS)(CO)9 in 90% yield. Similarly, the same reaction with toluene gives H3R~3(p3-CC6H4CH3)(C0)9 in 63% yield as an inseparable mixture of approximately equal amounts of two isomers, presumed to be ortho and para. Characterization of these two compounds by infrared, 'H NMR, and mass spectroscopy (see Experimental Section) gives results very similar to other H3Ru3(p3-CY)(C0),clusters. These reactions are very similar to the reported Friedel-Crafts reactions with C O ~ ( ~ ~ - C X ) ( C (XO=) ~C1, Br)., Halide Substitutions by Nucleophiles under Basic Conditions. Carboxylic acid derivatives of the methylidynetricobaltcluster are also produced from C O ~ ( ~ ~ - C X ) ( (X C O=) C1, ~ Br) with nucleophiles under basic conditions. Thus, Coj(p3CC02CH3)(C0), is formed with triethylamine in methanol and CO~(~~-CC(O)N(C,H,),)(CO)~ from diethylamine after 3.5 h in benzene.'O The mechanisms of these reactions are not well understood. Direct nucleophilic substitution is considered unlikely and carbonylated products are not always formed. For example, C O , ( ~ , - C S C ~ H ~ ) ( CisOformed )~ from (6) (7) (8)
(9)
(IO)
Keister and Horling Co3(p3-CCl)(CO), and benzethiol in the presence of trimethylamine. In contrast to the cobalt analogues, base-catalyzed nucleophilic attack on H3Ru3(p3-CBr)(C0),does not give carbonylated products. Treatment of an ethanolic solution with excess sodium ethoxide yields exclusively H3Ru3(p3COC2H,)(C0)9. Even under a carbon monoxide atmosphere the ester derivative is not formed; instead the ether product eliminates dihydrogen and is carbonylated to yield HRu,(pCOC2H5)(CO)lo.The infrared, 'H NMR, and mass spectra of these two species are fully comparable to those for the methyl analogues previously ~haracterized.~ Diethylamine also reacts differently with H3Ru3(p3CBr)(C0)9 than with the cobalt analogue. In either the presence or absence of carbon monoxide a slow reaction occurs at 50 OC to give exclusively HRu3(p-CN(C2Hs),)(CO),,. This compound is analogous to previously reported HRu,(p-CN(CH3)2)(CO)lo,for which the crystal structure has been determined,I2 and has been fully characterized. The presumed intermediate in this reaction, H,RU,(~,-CN(C~H~)~)(CO),, must be less stable than the final product because of the extra stabilization associated with the p-C-=NR," resonance form. This stabilization is, of course, more important with nitrogen than with oxygen, and it has proved impossible to hydrogenate HRU3(pL-CN(C2HS)2)(C0),0 to H3RU3(p3-CN(C2H5>2)(C0)9. Reduction with Tributyltin Hydride. The prototype methylidyne cluster is Co,(p,-CH)(CO), and the methylidyne analogues for ruthenium and osmium are important because of the special spectroscopic and chemical characteristics of the C-H bond. The osmium analogue H,Os3(p,-CH)(CO),. has been previously synthesized by Shapley and C a l ~ e r in t ~a~ two-step procedure from H 2 0 ~ 3 ( C 0 ) 1and 0 diazomethane, but this method cannot be used for the ruthenium cluster. We have prepared H3Ru3(p3-CH)(CO),by reduction of H3Ru3(p3-CBr)(CO), with tri-n-butyltin hydride. When a solution of the bromide derivative is heated at 50 O C in the presence of excess tri-n-butytin hydride, a slow reaction occurs over several hours, and after chromatography, H,Ru,(p,-CH)(CO), is isolated in 17% yield. The infrared spectrum of the simplest methylidynetriruthenium cluster is very similar to those of other members of the series (see Table I). As for H , O S ~ ( ~ ~ - C H ) ( Cthe O )methinyl ~ proton resonance occurs at very low field ( T 0.25), while the chemical shift of the three equivalent hydride ligands is similar to those of the other H3R~3(p3-CY)(C0)9 c l u ~ t e r s . ' ~The mass spectrum displays the molecular ion and ions derived from successive loss of carbonyls down to the bare Ru,C fragment. Reactions of H,Ru,(cL~-CB~)(CO), with Carbon Nucleophiles. Aryl Grignard reagents have been reported to give arylmethylidyne clusters in moderate yields from c03(&CX)(CO), (X = C1, Br).14 The mechanism for this reaction is not known, but it has been suggested that nucleophilic attack at a carbonyl ligand, forming an unstable metal acyl, is involved. However, no direct substitution is observed with alkyl Grignards; rather, all products are acid or ester derivatives formed upon destruction of the excess Grignard with water or alcohols. For H3Ru3(p3-CBr)(C0),three sites are available for attack by carbon nucleophiles-the methylidyne carbon, the carbonyl ligands, and the metal hydrides. In our hands no aryl derivatives have been isolated from reactions of this cluster with
'
(11) Seyferth, D.; Rudie, C. N.; Merola, J. S. J . Organornet. Chem. 1978, 144, C26. Shapley, J. R., personal communication. (12) Churchill, M. R.; DeBoer, B. G.; Rotella, F. J. Inorg. Chem. 1976, 15, 1843. Seyferth, D.; Williams, G. H.; Nivert, C. L. Inorg. Chem. 1977, 16, 758. The value for the ester C=O stretch for C O. ~ .( ~ ~ - C C O ~ C H ~is) ( C O )(13) ~ The chemical shift of the methinyl proton of CO,(CH)(CO)~is T -2.1 ~. (Seyferth, D.; Hallgren, J. E.; Hung, P. L. K. J . Organometal. Chem. 1695 cm-'. 1973, 50, 265). Dolby, R.; Robinson, B. H. J . Chem. SOC., Dalron Trans. 1972, 2046. (14) Dolby, R.; Robinson, B. H. J . Chem. SOC.,Dalton Trans. 1973, 1794. Seyferth, D.; Nivert, C. L. .IOrganornet. . Chem. 1976, 113, C65.
Inorg. Chem. 1980, 19. 2307-2315 LiC6H5, C6H5MgBr, or CH3C6H4MgBrunder conditions similar to those used for the cobalt clusters. Alkyl Grignards also gave no alkyl derivatives. Instead, in each case extensive decomposition occurred and the only compounds isolated were the starting material and the ether derivative H3Ru3(p3COCH3)(C0)9 resulting from reaction of H3Ru3(p3-CBr)(CO)9 with methanol during the workup. Discussion The physical and chemical properties of the H3M3(p3CY)(CO), series (M = Ru, Y = OCH,, OC2H5, C1, Br, C02CH3, C6H5, C,jH&H3, H; M = OS, Y = OCH3, OC2H5, Br) appear, as expected, to be similar in many respects to those of the well-known C O ~ ( ~ ~ - C Y ) ( C series. O ) ~ The methylidynetriruthenium clusters are, however, significantly less stable to oxygen or heat than the osmium or cobalt analogues. Additionally, the ruthenium and osmium clusters can undergo reactions involving loss of dihydrogen not available to the cobalt clusters. While this work has concerned almost exclusively ruthenium clusters, the osmium analogues are expected to behave similarly. The most significant difference between the methylidyne clusters of ruthenium and of cobalt observed in this work is revealed by the reactions of the halide derivatives with nucleophiles under basic reaction conditions. Both H3Ru3(p3CBr)(C0)9 and C O ~ ( ~ , - C B ~ ) ( Cform O ) ~"acylium" cations upon treatment with aluminum trichloride and carboxylic acid derivatives upon subsequent treatment with nucleophiles. However, while the cobalt cluster also forms such products from nucleophiles under basic conditions, e.g., c O 3 ( p 3 CC02CH3)(CO)gfrom methanol/triethylamine, H3Ru3(p3CBr)(C0)9 gives only ether products. This difference may
2307
be due to the greater propensity of cobalt for carbonylation reactions, but clearly the reasons for it are not understood and stabilities of the respective intermediate cations may be important. The hydride ligands of H,Ru,(~,-COR)(CO)~(R = CH,, C,H,) enable the cluster to undergo reactions not available to the cobalt analogue. At 100 "C under a carbon monoxide atmosphere H,RU(~,-COCH,)(CO)~ slowly loses dihydrogen and reverts to H R U ~ ( ~ - C O C H ~ ) ( CThe O ) ~p-COCH, ~. group is favorable because of the stabilization afforded by theC-=OCH3+ resonance form.5 This resonance form is more important for the amino derivatives because of the lower electronegativityof nitrogen and, thus, H3R~3(p3-CNR2)(CO)9 cannot be formed either by hydrogenation of HRu3(pCNR,)(CO),, or by attack of NHR, on H,Ru,(p,-CBr)(CO),. The methylidyne clusters H3M3(p3-CY)(C0)9may be expected to display an even richer chemistry than the cobalt series. These clusters offer possibilities for novel reactions involving loss of dihydrogen and coordination of donor ligands, as well as for coupling reactions involving the methylidyne fragment. Further work in this area is in progress. Registry No. H3Ru3(p3-CBr)(C0)9,73746-95-9;H3@3(&73746-97-1; CBr)(C0)9, 73746-96-0;H3R~3(p3-CC1)(C0)9, H~RU~(/L~-CCO~CH~)(CO)~, 73746-98-2; H~Ru~(/.L~-CC~H~)(CO)~, 73746-99-3;H~Ru~(/A~-CC~H~-O-CH~)(CO)~, 73747-00-9;H ~ R u J ( P ~ - C C ~ ~ H ~ - ~ - C H 73747-01-0; ~ ) ( C O ) ~ ,H ~ R u ~ ( ~ ~ - C O C ~ H ~ ) ( C O ) ~ , 73747-02-1;HRu~(~-CN(C~H~)~)(CO)~~, 73747-03-2;HjR~j(p371562-47-5; CH)(C0)9, 63280-43-3;H~Ru~(/+-COCH~)(CO)~, H30s3(p3-COCH3)(C0)9, 73747-04-3;BBr3, 10294-33-4;BC13, 10294-34-5; methanol, 67-56-1; benzene, 71-43-2; toluene, 108-88-3; ethanol, 64-17-5;diethylamine, 109-89-7.
Contribution from the Research School of Chemistry, The Australian National University, Canberra, A C T . 2600,Australia
Coordination Geometry of the Tridentate Chelating Ligand 2,2'-Bis( o-dipheny1phosphino)-trans-stilbene(bdpps). Crystal Structures of the Complexes (bdpps)C1Rhr*CH2C12,(bdpps)CIRhlIr, and (bdpps)Cl3Ir1Ir GLEN B. ROBERTSON,*' PAUL A. TUCKER, and PETER 0. WHIMP Received July 12, I979
The crystal and molecular structures of the complexes (bdpps)C1Rh1CH2Cl2,1, (bdpps)C13Rh"', 2, and (bdpps)Cl,Ir"', 3, (bdpps = o-Ph2PC6H4CH=CHC6H4PPh2-o),have been determined by three-dimensional X-ray structural analysis using data collected by counter methods. Compound 1 crystallizes in space group PI with u = 9.3781 (6)A, b = 20.7484 (10) A, c = 9.3768 (6)A, (Y = 93.12 (l)", p = 76.80,')l( y = 101.26 (l)", and Z = 2. Crystals of 2 and 3 are isomorphous, of space group C2/c,with Z = 4 and u = 17.3288(9)A, b = 10.6979 (6) A, c = 17.9021 (9) A, and /3 = 99.89 (1)O for 2 and a = 17.3352 (10) A, b = 10.7097 (6)A, c = 17.9308 (9) A, and fi = 99.86 (1)O for 3. The structures have been solved by conventional heavy-atom techniques and were refined by least-squares methods to final conventional R factors of 0.036 (1,4428 independent reflections), 0.020 (2,2391 reflections), and 0.033 (3, 2698 reflections). Important bond lengths are Rh(1)-C1 = 2.344 (2)A, Rh(II1)-C1 = 2.344(1) A, Ir(III)-Cl = 2.359 (1) A, Rh(1)-P = 2.285 (2)A, Rh(II1)-P = 2.385 (1) A, Ir(II1)-P = 2.383 (1) A, Rh(I)-C(olefin) = 2.101 (5) A, Rh(III)-C(olefin) = 2.238 (2)A, and Ir(III)-C(olefin) = 2.203 (3) A. In the M(II1) derivatives (2 and 3), the coordinated olefin is approximately parallel to the P-M-P axis, while in the Rh(1) derivative (l), the olefin is approximately perpendicular to this axis. The differences in orientation are shown to arise from a combination of electronic preferences with the simple geometric requirements of the chelating ligand.
'
Introduction It has been shown2that diphenyl-o-tolylphosphineundergoes a coupling and dehydrogenation reaction on heating with RhC13.3H20, in high-boiling alcohols, to give the complex
(bdpps)ClRh', 1 (bdpps = o-Ph2PC,H,-t-CH= CHC6H4PPh2-0, 41, in low Yield. Compound 1 is more efficiently Prepared by reacting 2,2'-bis(diPhenYlPhosPhino)dibenzyl with RhC13.3H20.3,4 Subsequent treatment with
(1) To whom correspondence should be addressed. ( 2 ) Bennett, M. A.; Longstaff, P. A. J . A m . Chem. SOC.1969, 91, 6266.
(3) Bennett, M. A.; Clark, P. W.; Robertson, G . B.; Whimp, P. 0. J . Chem. Soc., Chem. Commun. 1972, 101 1.
0020-1669/80/1319-2307$01.00/0
0 1980 American Chemical Society
